Friday, February 17, 2017
Latest on Lake Oroville
This second video below is annoyingly hysterical, but it does note the work being done to avoid the water flowing back into the powerhouse. Ignore all the fear mongering, but it does deal with this back flow issue that no one else is talking about.
My contact inside told me a week ago to watch for problems with debris and problems with water getting into the powerhouse, and here we have the first public evidence of that. They don't want water to back up the river into the powerhouse at the base of the dam proper, as that will damage their ability to control the spillway gates, and indeed all dam operations.
The other, as for now unmentioned risk for causing water to go back up the main river channel into the powerhouse is the possibility of huge uncontrolled water releases, over either of the two spillways, which certainly would put lots of water back upstream to the base of the dam, and thus into the powerhouse. Huge dam control problems could result if that happens, which could conceivably be as bad or worse than the loss of control of the emergency spillway. Imagine what would happen during the spring runoff if the water gets into the powerhouse, kills all their control of the dam, and the lake runs over the dam itself. While a very remote risk now, it is clear that the risk is not zero, that this risk has been recognized, and that efforts are now being made to plug the river between the two spillways and the powerhouse at the base of the dam. No official comment, to my knowledge, has been made on that.
Note as well the sloppy language when speaking of the "spillway." There are two, the emergency spillway, and the regular, concrete spillway. Both are separate problems.
The main spillway, which started the immediate problem by disintegrating, is currently handling the 100k out flow from the gates without further significant damage. The water flow over this spillway is controlled.
The emergency spillway is uncontrolled. No one directly controls flows over that except mother nature, and the incompetence of the water managers in letting the lake get too high. Once the Feather River flows over the emergency spillway, it is a wild river. This is where all the effort is going now, and it is all focused on the ground directly under the emergency spillway, which is just the bare earth. All the erosion immediately threatening the control of the river is there, very understandably. Whether these actions will help, or not, will only be known if more water goes over the emergency spillway and tests the work.
Remember, once the emergency spillway is overtopped, there is no control at all over water flows there.
Now, back to the regular concrete lined spillway. They are now pumping all the water they dare down that, and have written off for now the lower half, which is now destroyed. It appears that damage is not migrating up the spillway for now, and with these water flows, there is nothing at all they can do to repair it. The real risk is that this spillway begins again to come apart, and that damage moves up the spillway toward the gates. Then, they must stop the flows, and the river will go over the emergency spillway in huge uncontrolled flows. There is no immediate risk of that now, because the main spillway seems stable, but the managers really cannot know if that will continue.
The main dam is not at any risk now. There is a risk to the powerhouse and the controls of the dam, which sit at the base. No one is really speaking about that publicly, but they clearly are taking action to keep the water out.
So, in summary, three things to be concerned about. The emergency spillway first and immediately. Second, you can bet your bottom dollar that they are watching the main spillway with huge concern, but for now, that problem is stable. Finally, they must keep the debris from all this from backing water into the powerhouse, and now have applied huge earthmovers to do just that. Watch for that to bubble up in the next few weeks as a problem if they manage to keep water from going over the emergency spillway again.
So there you have it. I'd hate to live in Oroville right now. Even if they solve all these problems, and they get through the spring runoff with no disaster, the property values in little Oroville are going to crater.